Sulfur-tellurium-sulfur bond bridged dimer prodrug, nano assembly as well as preparation method and application of sulfur-tellurium-sulfur bond bridged dimer prodrug and nano assembly

Abstract

The invention relates to a sulfur-tellurium-sulfur bond bridged dimer prodrug, a nano assembly as well as a preparation method and application of the nano assembly, and belongs to the technical field of medicines. The structural formula of the sulfur-tellurium-sulfur bond bridged dimer prodrug is as shown in a general formula (I), and n is an integer from 1 to 5; the Rug is a drug molecule residue containing hydroxyl, amino or carboxyl, and the connection sites are oxygen atoms of hydroxyl, nitrogen atoms of amino or oxygen atoms of carboxyl. The preparation method is simple and easy to implement, the obtained sulfur-tellurium-sulfur connecting bond bridged dimer prodrugs at different positions can be self-assembled to form nanoparticles, the nanoparticles have oxidation-reduction dual-response drug release capacity, intelligent response activation of the prodrugs in tumor cells can be achieved, the anti-tumor effect and safety of the prodrugs are guaranteed, and the prodrugs have good application prospects. A new strategy is provided for developing a high-efficiency and low-toxicity drug delivery system. (I)

Description

Technical Field

[0001] This invention relates to a sulfur-telluride-sulfur bond-bridged dimer prodrug, a nano-assembly, its preparation method, and its application. Specifically, it relates to a redox-sensitive paclitaxel dimer prodrug, a dimer prodrug nano-assembly, and its preparation method, which are connected to the ester bond by sulfur-telluride-sulfur bonds at distances of one carbon atom (α-position), two carbon atoms (β-position), and three carbon atoms (γ-position), respectively, and their application in the preparation of antitumor drugs, belonging to the field of pharmaceutical technology. Background Technology

[0002] Cancer is one of the major public health challenges facing the world. In recent years, prodrug technology and nanotechnology have greatly enriched the delivery strategies for anti-tumor drugs, and several formulations have been successfully launched, such as capecitabine, paclitaxel for injection (albumin-bound), and doxorubicin hydrochloride liposomes. Prodrug technology can effectively improve the adverse properties of drugs by chemically modifying drug molecules; however, small molecule prodrugs still suffer from poor pharmacokinetic behavior and low tumor targeting efficiency. Nanoparticle drug delivery systems can effectively prolong the in vivo circulation time of drugs and can improve drug accumulation at tumor sites through active or passive targeting. However, traditional nanoparticle formulations often load drugs through physical encapsulation, resulting in low drug loading (generally less than 10%) and poor safety of carrier materials. In contrast, small molecule prodrug self-assembled nanoparticles combine the advantages of prodrugs and nanotechnology, resulting in high drug loading, avoiding adverse reactions caused by carrier materials, simple preparation processes, good reproducibility, and good application transformation potential.

[0003] Homodimeric prodrug nanoassemblies (HPNs) are nanoassemblies formed by linking two identical drug molecules together via chemically sensitive bonds and then preparing them through a simple one-step nanoprecipitation method. Because the prodrug serves as the structural unit of the nanoassembly, it exhibits extremely high drug loading capacity and avoids carrier-related toxicity issues, thus demonstrating good safety.

[0004] Despite their conceptual advantages, HPNs still face key technical challenges in practical applications. Many HPNs suffer from poor assembly capabilities due to imbalances in intermolecular forces, leading to rapid clearance in systemic circulation and hindering effective accumulation at the tumor site. Therefore, precisely regulating the structure of prodrug molecules to achieve a balance between assembly driving forces and steric hindrance, thereby enhancing the assembly stability and long-term circulation capability of HPNs, is a critical issue that urgently needs to be addressed. HPNs need to meet two seemingly contradictory requirements during in vivo delivery: maintaining high stability in systemic circulation (preventing premature drug leakage) while simultaneously releasing active drug molecules efficiently and rapidly upon reaching the tumor site. However, existing HPN designs based on single-response mechanisms (such as single reduction-sensitive bonds) often struggle to simultaneously achieve the ideal balance between "high stability in systemic circulation" and "efficient and rapid activation and release of drugs at the tumor site." More importantly, the complexity of the tumor microenvironment (such as redox heterogeneity) further exacerbates this challenge. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, this invention provides a thiotelluric acid-sulfur bond-bridged dimer prodrug, nanoassemblies, their preparation methods, and applications. Specifically, it involves designing and synthesizing paclitaxel dimer prodrugs and self-assembled nanoparticles bridged by thiotelluric acid bonds at different positions, along with their preparation methods and applications in the preparation of antitumor drugs. Furthermore, it explores the effects of thiotelluric acid-sulfur bond lengths on the stability, drug release, cytotoxicity, pharmacokinetics, tissue distribution, and pharmacodynamics of the prodrug nanoparticle assemblies. This provides new strategies and more options for developing intelligent responsive drug delivery systems for the tumor microenvironment, meeting the urgent clinical demand for highly effective chemotherapy agents.

[0006] A sulfur-tellurium-sulfur bond-bridged dimer prodrug, the prodrug having the structural formula shown in general formula (I):

[0007] (I) in, n is an integer from 1 to 5; Drug is a drug molecule residue containing hydroxyl, amino, or carboxyl groups, with the linkage site being the oxygen atom of the hydroxyl group, the nitrogen atom of the amino group, or the oxygen atom of the carboxyl group, respectively.

[0008] Preferably, the drug is a taxane or anthraquinone compound.

[0009] More preferably, the drug is paclitaxel.

[0010] Preferably, n is 1, 2, or 3.

[0011] More preferably, n is 1 or 3.

[0012] This invention selects paclitaxel (PTX) as a model drug and prepares a redox-sensitive paclitaxel dimer prodrug by linking the drug with 3,3'-telluride dithiodiacetic acid, 3,3'-telluride dithiodipropionic acid or 3,3'-telluride dithiodibutyric acid.

[0013] The structure of the paclitaxel dimer prodrug bridged by the α-thiotelluric thiocarboxyl bond is as follows:

[0014] α-PTX-STeS-PTX The structure of the paclitaxel dimer prodrug bridged by a β-thiotelluric bond is as follows:

[0015] β-PTX-STeS-PTX The structure of the paclitaxel dimer prodrug bridged by a γ-thiotelluric thiocarboxyl bond is as follows:

[0016] γ-PTX-STeS-PTX Preferably, the thiotelluric acid-thiosulfate bond-bridged dimer prodrug is a redox-sensitive paclitaxel dimer prodrug bridged by α- or γ-position thiotelluric acid-thiosulfate bonds.

[0017] This invention provides a method for preparing the above-mentioned sulfur-tellurium bond-bridged dimer prodrug, comprising the following steps: S1: 3,3'-telluride dithiocarboxylic acid (HOOC-(CH2) n -S-Te-S-(CH2) n 3,3'-telluride dithiodicarboxylic acid (3,3'-COOH) is dissolved in dichloromethane and stirred until homogeneous to obtain solution A, wherein the molar volume ratio of 3,3'-telluride dithiodicarboxylic acid to dichloromethane is 1 mmol: 20~60 ml; S2: Dissolve 4-dimethylaminopyridine (DMAP), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI), and a drug containing hydroxyl, amino, or carboxyl groups in anhydrous dichloromethane and stir until homogeneous to obtain solution B. The molar ratio of DMAP, EDCI, and the drug containing hydroxyl, amino, or carboxyl groups is 1:5~15:2.5~7.5, and the molar volume ratio of DMAP to dichloromethane is 1 mmol:50~150 ml. S3: Mix solution A and solution B, stir at room temperature for 10-12 h under N2 protection, then add EDCI and DMAP, continue stirring at room temperature for 12-24 h, and purify to obtain the solution. The volume ratio of solution A to solution B is 1:1-5.

[0018] The present invention provides a nano-assembly based on the above-mentioned sulfur-tellurium-sulfur bond-bridged dimer prodrug, wherein the nano-assembly is a non-PEGylated dimer prodrug nano-assembly or a dimer prodrug nano-assembly modified with a PEG modifier.

[0019] The present invention also provides a method for preparing the above-mentioned nano-assemblies, comprising the following steps: dissolving a sulfur-tellurium-sulfur bond-bridged dimer prodrug in a solvent, or dissolving a sulfur-tellurium-sulfur bond-bridged dimer prodrug and a PEG modifier in a solvent, and slowly adding the solution dropwise to water while stirring, wherein the prodrug spontaneously forms uniform nanoparticles, and removing the solvent by vacuum distillation to obtain a nano-colloidal solution free of organic solvents.

[0020] Furthermore, the sulfur-tellurium sulfur bond-bridged dimer prodrug is the sulfur-tellurium sulfur bond-bridged dimer prodrug described above.

[0021] Further, the PEG modifier is one or more of TPGS, DSPE-PEG, PLGA-PEG or PE-PEG, with a molecular weight of 1000~5000.

[0022] Preferably, the PEG modifier is DSPE-PEG.

[0023] Preferably, the molecular weight of the PEG is 1000, 2000 or 5000, more preferably 2000.

[0024] Further, the solvent is one or more selected from ethanol, dimethyl sulfoxide, N,N'-dimethylformamide, tetrahydrofuran, or acetone.

[0025] Furthermore, the mass ratio of the sulfur-tellurium-sulfur bond-bridged dimer prodrug to the PEG modifier is 1:0.1~0.45. Under these conditions, the prodrug nanoassembly can exert a better anti-tumor effect.

[0026] The present invention provides a pharmaceutical composition comprising the above-described sulfur-tellurium-sulfur bond-bridged dimer prodrug or the above-described nanoassembly and a pharmaceutically acceptable carrier or excipient.

[0027] The present invention also provides the use of the above-mentioned sulfur-tellurium-sulfur bond-bridged dimer prodrug, or the above-mentioned nanoassembly, or the above-mentioned pharmaceutical composition in the preparation of antitumor drugs.

[0028] Furthermore, the application of the sulfur-tellurium-sulfur bond-bridged dimer prodrug, nanoassembly, or pharmaceutical composition in the preparation of a drug delivery system.

[0029] Furthermore, the application of the sulfur-tellurium-sulfur bond-bridged dimer prodrug, nanoassembly, or pharmaceutical composition in the preparation of injection, oral, or topical drug delivery systems.

[0030] The sulfur-tellurium-sulfur bond provided by this invention is a sulfur hybrid bond formed by the combination of two elements. Due to its special atomic arrangement, the electron cloud density of the connecting bond is unevenly distributed, providing dual redox reaction sites. It has been proven to have dual redox response characteristics.

[0031] Furthermore, this invention introduces α-thiotelluric thiosulfate bonds into prodrugs and nanoassemblies, designing redox-sensitive dimeric prodrugs bridged by α-thiotelluric thiosulfate bonds. These dimeric prodrugs are then used in the construction of nanoassemblies, achieving good chemical stability, high drug loading, good assembly stability, low toxicity, and rapid, tumor-specific drug release, thus improving therapeutic efficacy. Simultaneously, using dimeric prodrugs with β-thiotelluric thiosulfate bonds and γ-thiotelluric thiosulfate bonds as controls, the differences in self-assembly, redox-sensitive response, and antitumor activity of different linker chain lengths were investigated, as well as their impact on the stability, drug release, cytotoxicity, pharmacokinetics, tissue distribution, and pharmacodynamics of the prodrug self-assembled nanoparticles.

[0032] The beneficial effects of this invention are: (1) The present invention designs and synthesizes dimer prodrugs with sulfur-tellurium bonds at different positions and their uniform dimer prodrug self-assembled nanoparticles. The preparation method is simple and easy to implement. The self-assembled nanoparticles can achieve efficient drug loading with a drug loading of more than 60%. They also have good stability after being placed in 10% FBS phosphate buffer for 24 h and the particle size remains basically unchanged after being placed at room temperature for 30 days. (2) This invention investigated the differences in self-assembly, redox-sensitive response, and antitumor activity of thiotelluride-thiocarboxylates of different lengths, and explored the effects of prodrug nanoassemblies on stability, drug release, cytotoxicity, pharmacokinetics, tissue distribution, and pharmacodynamics. Based on the combined experimental results, the α-thiotelluride-thiocarboxylate prodrug exhibits higher redox-sensitive properties, better addressing the redox heterogeneity of the tumor microenvironment. Simultaneously, the α-thiotelluride-thiocarboxylate prodrug nanoassembly also possesses the best assembly capability. This invention provides new strategies and more options for developing intelligent responsive drug delivery systems for the tumor microenvironment, meeting the urgent clinical demand for highly effective chemotherapeutic agents. Attached Figure Description

[0033] Figure 1 This is a structural diagram of the α-thiotelluric acid-thiosulfate bond-bridged paclitaxel dimer prodrug (α-PTX-STeS-PTX) obtained in Example 1 of the present invention, wherein A is the α-PTX-STeS-PTX 1 B is the H-NMR spectrum, B is the mass spectrum of α-PTX-STeS-PTX, and C is the high-performance liquid chromatography purity spectrum of α-PTX-STeS-PTX.

[0034] Figure 2This is a structural diagram of the β-PTX-STeS-PTX dimeric prodrug bridged by a thiotelluric acid bond obtained in Example 2 of the present invention, wherein A is the structure of β-PTX-STeS-PTX. 1 B is the H-NMR spectrum, B is the mass spectrum of β-PTX-STeS-PTX, and C is the high-performance liquid chromatography purity spectrum of β-PTX-STeS-PTX.

[0035] Figure 3 The diagram shows the structure of the γ-PTX-STeS-PTX dimeric prodrug (γ-PTX-STeS-PTX) obtained in Example 3 of this invention, where A is the 1H-NMR spectrum of γ-PTX-STeS-PTX, B is the mass spectrum of γ-PTX-STeS-PTX, and C is the high-performance liquid chromatography purity spectrum of γ-PTX-STeS-PTX.

[0036] Figure 4 The images show the particle size distribution and transmission electron microscope (TEM) images of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric thiobonds prepared in Example 4 of this invention. In the image, A is the particle size distribution of the self-assembled nanoparticles of the paclitaxel dimer prodrug with different positions of thiotelluric thiobonds, and B is the TEM image of the self-assembled nanoparticles of the paclitaxel dimer prodrug with different positions of thiotelluric thiobonds.

[0037] Figure 5 This is a particle size-colloidal stability diagram of the PEGylated paclitaxel dimer prodrug nanoassemblies with thiotelluric bonds at different positions in Example 5 of the present invention.

[0038] Figure 6 This is a room temperature stability diagram of the non-PEGylated paclitaxel dimer prodrug nanoassemblies with thiotelluric bonds at different positions in Example 6 of the present invention. In this diagram, A is the particle size change of the non-PEGylated paclitaxel dimer prodrug nanoassemblies after 48 hours of room temperature storage, and B is the particle size polydispersity index change of the non-PEGylated paclitaxel dimer prodrug nanoassemblies after 48 hours of room temperature storage.

[0039] Figure 7 This is a diagram showing the assembly force competition experiment of PEGylated paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric thiobonds in Example 7 of the present invention. In this diagram, A represents the particle size and dispersibility index of the paclitaxel dimer prodrug nanoassemblies after incubation with SDS, a hydrophobic force competing reagent, at different concentrations; B represents the particle size and dispersibility index of the paclitaxel dimer prodrug nanoassemblies after incubation with Urea, a hydrogen bonding force competing reagent, at different concentrations; and C represents the particle size and dispersibility index of the paclitaxel dimer prodrug nanoassemblies after incubation with NaCl, an electrostatic force competing reagent, at different concentrations.

[0040] Figure 8The images show in vitro release assays of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds in Example 8 of this invention. Specifically, A shows the in vitro release assay of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds under 0.01 mM GSH; B shows the in vitro release assay of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds under 0.1 mM GSH; C shows the in vitro release assay of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds under 1 mM GSH; D shows the in vitro release assay of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds under 1 mM H2O2; and E shows the in vitro release assay of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds under 10 mM GSH. The in vitro release test diagram under H2O2 conditions is shown in Figure F, which is the in vitro release test diagram of paclitaxel dimer prodrug nanoassemblies with thiotelluric bonds at different positions under 50 mM H2O2 conditions.

[0041] Figure 9 The diagram shows the cytotoxicity of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds in Example 9 of this invention. In the diagram, A represents the half-maximal inhibitory concentration (IC50) of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds against 4T1 cells, B represents the IC50 of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds against A549 cells, and C represents the IC50 of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds against L02 cells.

[0042] Figure 10 This is a blood drug concentration-time curve of the paclitaxel dimer prodrug nanoassembly with thiotelluric bonds at different positions in Example 10 of the present invention.

[0043] Figure 11 The figures shown are from Example 11 of this invention and illustrate the in vivo antitumor experiment of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds. A represents the effect of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds on the growth of subcutaneous breast cancer tumors in Balb / C mice; B represents the effect of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds on the tumor bearing rate in Balb / C mice; C represents tumor photographs of Balb / C tumor-bearing mice after treatment with the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds; and D represents the effect of the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds on the body weight of tumor-bearing mice. Detailed Implementation

[0044] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way.

[0045] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are commercially available unless otherwise specified.

[0046] Example 1 Synthesis of α-PTX-STeS-PTX, a paclitaxel dimer prodrug bridged by an α-thiotellurium-sulfur bond: 0.25 mmol of 3,3'-telluride dithiodiacetic acid was dissolved in 10 mL of dichloromethane. Separately, 0.05 mmol of 4-dimethylaminopyridine (DMAP), 1 mmol of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI), and 0.5 mmol of paclitaxel were dissolved in 20 mL of anhydrous dichloromethane and mixed with the 3,3'-telluride dithiodiacetic acid solution in dichloromethane. The mixture was stirred at room temperature for 10–12 h. Then, 0.5 mmol of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.05 mmol of 4-dimethylaminopyridine were added, and the mixture was stirred at room temperature for 12–24 h. The entire reaction was carried out under N2 protection. The resulting product was purified by preparative liquid chromatography.

[0047] The structure of α-PTX-STeS-PTX prepared in Example 1 was determined by mass spectrometry and proton nuclear magnetic resonance spectroscopy, and the results are as follows: Figure 1 As shown.

[0048] The nuclear magnetic resonance spectral analysis results are as follows: α-PTX-STeS-PTX 1H NMR (600 MHz, Chloroform-d) δ 8.13 (d, J = 7.4 Hz, 4H, Ar-H), 7.72(d, J = 7.4 Hz, 4H, Ar-H), 7.61 (t, J = 7.4 Hz, 2H, Ar-H), 7.54 – 7.48 (m,6H, Ar-H), 7.43 - 7.36 (m, 12H, Ar-H), 7.34 (t, J = 7.1 Hz, 2H, Ar-H), 7.09(d, J = 9.3 Hz, 2H, 2*-CONH-), 6.30 (s, 2H, 10.10a-H), 6.23 (t, J = 9.0 Hz,2H, 3',3''-H), 6.01 (dd, J = 9.3, 3.3 Hz, 2H, 2',2''-H), 5.69 (d, J = 7.1 Hz, 2H, 13,13a-H), 5.53 (d, J = 3.3 Hz, 2H, 2*-OH), 4.98 (dd, J = 9.6, 2.5 Hz, 2H, 2,2a-H), 4.47 – 4.39 (m, 2H, 7,7a-H), 4.32 (d, J = 8.4 Hz, 2H, 20,20a-αCH2), 4.21 (d, J = 8.5 Hz, 2H, 20,20a-βCH2), 4.06 – 3.93 (m, 4H, -CO CH 2STeS CH 2CO-), 3.80 (d, J = 7.2 Hz, 2H, 5.5a-H), 2.55 (ddd, J = 14.7, 9.6, 6.5 Hz, 2H, 3.3a-H), 2.43 (s, 6H, 2*-OCO CH 3), 2.35 (dd, J = 15.3, 9.3 Hz, 2H,14,14a-αCH2), 2.25 - 2.18 (m, 8H, 2*-OCO CH 3, 14,14a-βCH2), 1.93 – 1.86 (m, 8H,6,6a-αCH2, 18,18a-CH3), 1.73 - 1.55 (m, 8H,19,19a-CH3, 6,6a-βCH2), 1.22 (s,6H,16,16a- CH 3), 1.14 (s, 6H, 17,17a- CH 3)

[0049] The mass spectrometry results are as follows: MS (ESI) m / z [M+H] + =1983.52491. The purity results show that the purity of α-PTX-STeS-PTX is 99.24%, which meets the requirements for subsequent experiments.

[0050] Example 2 The β-thiotelluric acid-bridged paclitaxel dimer prodrug (β-PTX-STeS-PTX) was synthesized using the preparation method in Example 1, by replacing 3,3'-telluride dithiodiacetic acid with 3,3'-telluride dithiodipropionic acid to obtain the β-thiotelluric acid-bridged paclitaxel dimer prodrug.

[0051] The structure of β-PTX-STeS-PTX prepared in Example 2 was determined by mass spectrometry and proton nuclear magnetic resonance spectroscopy, and the results are as follows: Figure 2 As shown.

[0052] The nuclear magnetic resonance spectral analysis results are as follows: β-PTX-STeS-PTX 1H NMR (600 MHz, Chloroform-d) δ 8.13 (d, J = 7.2 Hz, 4H, Ar-H), 7.73(d, J = 7.2 Hz, 4H, Ar-H), 7.61 (t, J = 7.4 Hz, 2H, Ar-H), 7.54 – 7.47 (m,6H, Ar-H), 7.43 - 7.36 (m, 12H, Ar-H), 7.34 (t, J = 7.2 Hz, 2H, Ar-H), 6.99 (d, J = 9.3 Hz, 2H, 2*-CONH-), 6.30 (s, 2H, 10.10a-H), 6.24 (td, J = 9.1, 1.6Hz, 2H, 3',3''-H), 5.97 (dd, J = 9.2, 3.6 Hz, 2H, 2',2''-H), 5.68 (d, J = 7.1 Hz, 2H, 13,13a-H), 5.53 (d, J = 3.6 Hz, 2H, 2*-OH), 4.97 (dd, J = 9.6, 2.5 Hz, 2H, 2,2a-H), 4.47 – 4.41 (m, 2H, 7,7a-H), 4.32 (d, J = 8.4 Hz, 2H, 20,20a-αCH2), 4.20 (d, J = 8.5 Hz, 2H, 20,20a-βCH2), 3.80 (d, J = 7.1 Hz, 2H, 5.5a-H), 3.35 - 3.22 (m, 4H, - CH 2STeS CH 2-), 2.86 – 2.73 (m, 4H, -CO CH 2CH2STeSCH2 CH 2CO-), 2.62 - 2.48 (m, 4H, 3,3a-H, 2*-OH), 2.44 (s, 6H, 2*-OCO CH 3), 2.34 (dd, J = 15.3, 9.4 Hz, 2H, 14.14a-αCH2), 2.22 (s, 6H, 2*-OCO CH3), 2.15 (dd, J = 15.4, 8.9 Hz, 2H, 14,14a-βCH2), 1.93 (s, 6H, 18,18a-CH3), 1.88 (ddd, J = 13.7, 11.0, 2.5 Hz, 2H, 6,6a-αCH2), 1.81 - 1.75 (m, 2H,6,6a-βCH2), 1.68 (s, 6H, 19,19a-CH3), 1.22 (s, 6H, 16,16a- CH 3), 1.13 (s, 6H,17,17a- CH 3).

[0053] The mass spectrometry results are as follows: MS (ESI) m / z [M+Na] + =2033.54748. The purity results show that the purity of β-PTX-STeS-PTX is 99.60%, which meets the requirements for subsequent experiments.

[0054] Example 3 Using the preparation method of Example 1, γ-thiotelluric acid dithiocarbamate was replaced with 3,3'-thiotelluric acid dithiocarbamate to prepare paclitaxel dimer prodrug with thiotelluric acid bond bridged at the γ-position.

[0055] The structure of γ-PTX-STeS-PTX prepared in Example 3 was determined by mass spectrometry and proton nuclear magnetic resonance spectroscopy, and the results are as follows: Figure 3 As shown.

[0056] The nuclear magnetic resonance spectral analysis results are as follows: γ-PTX-STeS-PTX 1H NMR (600 MHz, Chloroform-d) δ 8.14 (d, J = 7.0 Hz, 4H, Ar-H), 7.73(d, J = 7.0 Hz, 4H, Ar-H), 7.61 (t, J = 7.4 Hz, 2H, Ar-H), 7.54 – 7.47 (m,6H, Ar-H), 7.44 – 7.32 (m, 14H, Ar-H), 6.94 (d, J = 9.2 Hz, 2H, 2*-CONH-),6.29 (s, 2H, 10,10a-H), 6.24 (td, J = 9.1, 1.6 Hz, 2H, J = 9.1, 1.6 Hz, 2H,3',3''-H), 5.97 (dd, J = 9.2, 3.3 Hz, 2H, 2',2''-H), 5.68 (d, J = 7.1 Hz, 2H, 13,13a-H), 5.52 (d, J = 3.3 Hz, 2H, 2*-OH), 4.97 (dd, J = 9.6, 2.5 Hz, 2H, 2,2a-H), 4.47 – 4.41 (m, 2H, 7,7a-H), 4.31 (d, J = 8.3 Hz, 2H, 20,20a-αCH2), 4.20 (d, J = 8.7 Hz, 2H, 20,20a-βCH2), 3.81 (d, J = 7.1 Hz, 2H, 5,5a-H), 3.13– 3.00 (m, 4H, - CH 2STeS CH 2-), 2.60 – 2.48 (m, 8H, -CO CH 2CH2CH2STeSCH2CH2 CH 2CO-,3,3a-H, 2*-OH), 2.45 (s, 6H, 2*-OCO CH 3), 2.36 (dd, J = 15.3, 9.3 Hz, 2H, 14.14a-αCH2), 2.21 (s, 6H, 2*-OCO CH 3), 2.15 (dd, J = 15.3, 9.0 Hz, 2H, 14.14a-βCH2), 1.99 - 1.95 (m, 4H,- CH 2CH2STeSCH2 CH2-), 1.93 (s, 6H, 18,18a-CH3), 1.88(ddd, J = 14.6, 11.0, 2.5 Hz, 2H, 6,6a-αCH2), 1.71 - 1.65 (m, 8H , 6,6a-βCH2,19,19a-CH3), 1.22 (s, 6H, 16,16a- CH 3), 1.13 (s, 6H, 17,17a- CH 3).

[0057] The mass spectrometry results are as follows: MS (ESI) m / z [M+Na] + =2061.57315. The purity results show that the purity of γ-PTX-STeS-PTX is 99.20%, which meets the requirements for subsequent experiments.

[0058] Example 4 Preparation of paclitaxel dimer prodrug nanoassemblies bridged by thiotelluric bonds at different positions: Paclitaxel dimer prodrug nanoassemblies bridged by thiotelluric bonds at different positions: Accurately weigh DSPE-PEG 2k 2 mg of paclitaxel dimer prodrugs and 8 mg of thiotelluric-thiobin bridged at different positions obtained in Examples 1-3 were mixed separately and dissolved in 1 mL of ethanol. While stirring, the ethanol solution was slowly added dropwise to 4 mL of deionized water, spontaneously forming uniform nanoparticles α-PTX-STeS-PTX NAs, β-PTX-STeS-PTX NAs, and γ-PTX-STeS-PTX NAs. The ethanol was removed by rotary evaporation under reduced pressure to obtain a nanocolloidal solution free of organic reagents. The results are as follows... Figure 4 As shown, the particle size of each group of nanoparticles is around 80~120 nm, and the particle size is uniform. The transmission electron microscopy image shows that the nano-assemblies are uniform spherical.

[0059] DiR-labeled thiotelluric bonds bridging paclitaxel dimer prodrug nanoassemblies: Accurately weigh DSPE-PEG 2k 2.15 mg of paclitaxel dimer prodrugs with different positions of thiotelluric-thiobonds obtained in Examples 1-3, and 3 mg of DiR powder were mixed separately and dissolved in 2.15 mL of ethanol. While stirring, the ethanol solution was slowly added dropwise to 8.6 mL of deionized water, spontaneously forming uniform nanoparticles α-PTX-STeS-PTX NAs, β-PTX-STeS-PTX NAs, and γ-PTX-STeS-PTX NAs. The ethanol was removed by rotary evaporation under reduced pressure to obtain a nanocolloidal solution free of organic reagents.

[0060] Example 5 Colloidal stability testing of paclitaxel dimer prodrug nanoassemblies bridged by thiotellurium bonds at different positions: The room temperature stability of the paclitaxel dimer prodrug nanoassemblies bridged by thiotelluric bonds at different positions prepared in Example 4 was investigated, and the results are as follows: Figure 5 As shown, the prepared PEG-modified paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric bonds did not show significant changes in particle size after being stored at room temperature for 30 days, indicating good long-term storage stability at room temperature.

[0061] One mL of the paclitaxel dimer prodrug nanoassemblies bridged by thiotelluric bonds at different positions was taken and added to 20 mL of phosphate-buffered saline (PBS, pH 7.4) containing 10% FBS. The mixture was incubated at 37°C for 48 h, and the particle size change was measured by dynamic light scattering at predetermined time points (0, 1, 2, 4, 6, 12, 24, and 48 h). The results are as follows: Figure 6 As shown, α-PTX-STeS-PTX NAs and β-PTX-STeS-PTX NAs exhibit good colloidal stability, with no significant change in particle size within 48 h. In contrast, γ-PTX-STeS-PTX NAs nanoparticles show poor colloidal stability, with particle size increasing with prolonged incubation time.

[0062] Example 6 Assembly force competition test of paclitaxel dimer prodrug nanoassemblies with thiotellurium-thiosulfate bonds at different positions: The paclitaxel dimer prodrug self-assembled nanoparticles with different positions of thiotelluric bonds bridged by thiotelluric bonds prepared in Example 4 were incubated with 0.1 mol / L sodium dodecyl sulfate (SDS), a hydrophobic interaction competing agent; urea, a hydrogen bonding competing agent; and sodium chloride (NaCl), an ionic interaction competing agent. The particle size was measured at specific times, and the results are as follows: Figure 7 As shown, it can be seen that the three nanoassemblies are mainly assembled through hydrophobic interactions. α-PTX-STeS-PTX NAs and β-PTX-STeS-PTXNAs exhibit smaller particle size variations, showing stronger assembly stability compared to γ-PTX-STeS-PTX NAs.

[0063] Example 7 In vitro release assays of paclitaxel dimer prodrug nanoassemblies with thiotellurium-thiosulfate bonds at different positions: Using phosphate-buffered saline (PBS) containing 30% ethanol at pH 7.4 as the release medium, the in vitro release of paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds was investigated. 1 mL of PEG-modified paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric sulfide bonds (paclitaxel content 200 μg / mL) prepared in Example 4 was added to 30 mL of release medium. Certain concentrations of glutathione (GSH, 0.01 mM, 0.1 mM, 1 mM) or hydrogen peroxide (H2O2, 1 mM, 10 mM, 50 mM) were added to the release medium. Samples were taken at set time points at 37°C, and the concentration of released paclitaxel was determined by high-performance liquid chromatography (HPLC) to investigate the release of the nanoassemblies under oxidizing and reducing conditions. The results are as follows: Figure 8 As shown, all the dimer nanoassemblies exhibit redox-responsive release characteristics. The order of reduction sensitivity is γ-PTX-STeS-PTX NAs > α-PTX-STeS-PTX NAs > β-PTX-STeS-PTX NAs. The order of oxidation responsiveness is described as follows: α-PTX-STeS-PTX NAs > γ-PTX-STeS-PTX NAs > β-PTX-STeS-PTX NAs. β-PTX-STeS-PTX NAs release the least amount of paclitaxel, while α-PTX-STeS-PTX NAs exhibit extremely high dual redox responsiveness.

[0064] Example 8 Cytotoxicity testing of paclitaxel dimer prodrug nanoassemblies with thiotellurium-thiosulfate bonds at different positions: The MTT assay was used to investigate the toxicity of paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluride-thiosulfate bonds to two types of tumor cell lines and one type of normal cell line (mouse breast cancer (4T1) cells, human lung cancer (A549) cells, and normal human liver (L02) cells). First, morphologically sound cells were digested, diluted with culture medium to 5000 cells / mL, and then 100 μL of cell suspension was added to each well of a 96-well plate. The plates were incubated for 24 h to allow cell adhesion. After cell adhesion, either paclitaxel or the paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluride-thiosulfate bonds prepared in Example 4 were added. In this experiment, the drug solution and nanoparticle formulation were prepared and diluted using the corresponding cell culture medium and aseptically filtered through a 0.22 μm filter membrane. 100 μL of the test solution was added to each well, with three parallel wells for each concentration. The control group, i.e., without the test drug solution, was supplemented with 100 μL of culture medium and incubated with the cells in an incubator. Forty-eight hours after drug addition, the 96-well plate was removed, and 20 μL of 5 mg / mL MTT solution was added to each well. The plate was incubated for 4 hours, and the culture medium was discarded. The 96-well plate was then inverted onto filter paper to thoroughly absorb any remaining liquid. 200 μL of DMSO was added to each well, and the plate was shaken for 10 minutes to dissolve the blue-purple crystals. Well A1 (containing only 200 μL of DMSO) was designated as the zeroing well. The absorbance of each well after zeroing was measured at 570 nm using a microplate reader.

[0065] The results are as follows Figure 9 As shown, since the prodrugs require activation to exert their effects in cells, the cytotoxicity of the three dimeric prodrug nanoassemblies was weaker than that of paclitaxel solution. The cytotoxicity of the dimeric prodrug nanoassemblies was closely related to their redox activation capacity. The order of antitumor activity of the four dimeric prodrug nanoassemblies was: α-PTX-STeS-PTX NAs > γ-PTX-STeS-PTX NAs > β-PTX-STeS-PTX NAs. α-PTX-STeS-PTX NAs, due to their dual redox hypersensitivity, could effectively cope with the heterogeneous microenvironment of tumor cells, thus exhibiting the strongest in vitro antitumor activity.

[0066] Example 9 Pharmacokinetic study of paclitaxel dimer prodrug nanoassemblies with thiotelluric bonds at different positions: SD rats weighing 200–250 g were randomly divided into groups and fasted for 12 h before administration, with free access to water. DiR solution and DiR-labeled paclitaxel dimer prodrug nanoassemblies with different positions of thiotelluric-thiobonds prepared in Example 4 (equal DiR 2 mg / kg) were administered intravenously. The paclitaxel dose was 5 mg / kg. Blood was collected from the orbital sinus at specified time points, and plasma was obtained. The fluorescence intensity of DiR in different groups was measured using a multi-mode microplate reader.

[0067] Experimental results are as follows Figure 10 As shown, due to its short half-life, the DiR solution was rapidly cleared from the bloodstream. In contrast, the cycling time of the paclitaxel dimer prodrug self-assembled nanoparticles was significantly prolonged. Furthermore, different linker chain lengths significantly affected the pharmacokinetic behavior of the sulfur-tellurium sulfur dimer prodrug nanoassemblies. Compared to γ-PTX-STeS-PTX NAs, α-PTX-STeS-PTX NAs and β-PTX-STeS-PTX NAs exhibited longer in vivo circulation times due to their stronger assembly stability.

[0068] Example 10 In vivo antitumor experiments of paclitaxel dimer prodrug nanoassemblies with thiotellurium-thiosulfate bonds at different positions: Using 4T1 tumor-bearing BALB / c mice as a model, paclitaxel dimer prodrug nanoassemblies with thiotelluric bonds bridged at different locations were administered via tail vein. Control groups included intravenous administration of paclitaxel, paclitaxel albumin, and saline. Results are as follows: Figure 11 As shown, compared with the saline group, the α-PTX-STeS-PTX NAs, β-PTX-STeS-PTX NAs, and γ-PTX-STeS-PTX NAs groups slowed tumor growth to some extent. In contrast, paclitaxel and α-PTX-STeS-PTX NAs showed higher antitumor effects. This is because α-PTX-STeS-PTX NAs have good colloidal stability, which improves their pharmacokinetic behavior and results in a longer in vivo circulation time. Simultaneously, α-PTX-STeS-PTX NAs have a faster drug release rate in tumor cells, enhancing their cytotoxicity. However, the paclitaxel group showed a significant decrease in body weight, while the dimer prodrug nanoparticle groups did not, indicating that α-PTX-STeS-PTX NAs have better safety while exhibiting comparable antitumor activity to paclitaxel.

[0069] In summary, the stability, cytotoxicity, pharmacokinetic distribution, and tumor site-responsive drug release of nanoparticles all affect the final antitumor effect. The above results once again demonstrate the advantages of the thiotelluric bond-bridged paclitaxel dimer prodrug nanoassemblies.

Claims

1. A sulfur-tellurium bond-bridged dimer prodrug, characterized in that: The prodrug has the structural formula shown in general formula (Ⅰ): （Ⅰ） in, n is an integer from 1 to 5; Drug is a drug molecule residue containing hydroxyl, amino, or carboxyl groups, with the linkage site being the oxygen atom of the hydroxyl group, the nitrogen atom of the amino group, or the oxygen atom of the carboxyl group, respectively.

2. The sulfur-tellurium bond-bridged dimer prodrug according to claim 1, characterized in that: The drug is a taxane or anthraquinone compound.

3. The sulfur-tellurium bond-bridged dimer prodrug according to claim 1 or 2, characterized in that: The drug in question is paclitaxel.

4. The sulfur-tellurium bond-bridged dimer prodrug according to claim 1, characterized in that: n is 1, 2, or 3.

5. The sulfur-tellurium bond-bridged dimer prodrug according to claim 1, characterized in that: The prodrug is one of the following compounds: 。 6. The method for preparing the sulfur-tellurium-sulfur bond-bridged dimer prodrug according to claim 1, characterized in that: Includes the following steps: S1: 3,3'-telluride dithiocarboxylic acid (HOOC-(CH2) n -S-Te-S-(CH2) n 3,3'-telluride dithiodicarboxylic acid (3,3'-COOH) is dissolved in dichloromethane and stirred until homogeneous to obtain solution A, wherein the molar volume ratio of 3,3'-telluride dithiodicarboxylic acid to dichloromethane is 1 mmol : 20~60 ml; S2: Dissolve 4-dimethylaminopyridine (DMAP), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI), and a drug containing hydroxyl, amino, or carboxyl groups in anhydrous dichloromethane and stir until homogeneous to obtain solution B. The molar ratio of DMAP, EDCI, and the drug is 1:5~15:2.5~7.5, and the molar volume ratio of DMAP to dichloromethane is 1 mmol:50~150 ml. S3: Mix solution A and solution B, stir at room temperature for 10-12 h under N2 protection, then add EDCI and DMAP, continue stirring at room temperature for 12-24 h, and purify to obtain the solution. The volume ratio of solution A to solution B is 1:1-5.

7. A nanoassembly based on the sulfur-tellurium bond-bridged dimer prodrug of claim 1, characterized in that: The nanoassemblies are either non-PEGylated dimer prodrug nanoassemblies or dimer prodrug nanoassemblies modified with PEG modifiers.

8. The method for preparing the nano-assembly according to claim 7, characterized in that: The sulfur-tellurium-sulfur bond-bridged dimer prodrug was dissolved in a solvent, or the sulfur-tellurium-sulfur bond-bridged dimer prodrug and the PEG modifier were dissolved in a solvent. While stirring, the solution was slowly added dropwise to water. The prodrug spontaneously formed uniform nanoparticles. The solvent was removed by vacuum distillation to obtain a nanocolloidal solution free of organic solvents. The sulfur-tellurium sulfur-linked dimer prodrug is the sulfur-tellurium sulfur-linked dimer prodrug as described in claim 1. The PEG modifier is one or more of TPGS, DSPE-PEG, PLGA-PEG or PE-PEG, with a molecular weight of 1000~5000. The solvent is one or more selected from ethanol, dimethyl sulfoxide, N,N'-dimethylformamide, tetrahydrofuran, or acetone; The mass ratio of the sulfur-tellurium-sulfur bond-bridged dimer prodrug to the PEG modifier is 1:0.1~0.

45.

9. A pharmaceutical composition, characterized in that: The pharmaceutical composition comprises the thiotelluric-thio-linked dimer prodrug of claim 1 or the nanoassembly of claim 7 and a pharmaceutically acceptable carrier or excipient.

10. The use of the sulfur-tellurium-sulfur bond-bridged dimer prodrug of claim 1, the nanoassembly of claim 7, or the pharmaceutical composition of claim 9 in the preparation of an antitumor drug.

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